JP2004134890A - Image sensor and image reader provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image sensor capable of obtaining an image with high quality at a low cost and an image reader provided with the same. <P>SOLUTION: The image sensor includes: light sources 22, 23 for emitting light to an original S; a light receiving section 25 for receiving a reflected light from the original S; and an image forming element 24 to guide the reflected light from the original S to the light receiving section 25, which are all integrally contained in a case 27. A color cut film 28 for absorbing the light of a particular wavelength included in the light from the light sources 22, 23 is inserted and held between the imaging element 24 and the case 27. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a structure of a contact image sensor, and more particularly, to a contact image sensor having a color cut film mounted inside a housing of the sensor.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a reading device of a copying machine, a reading device using a reduction optical system is widely known. FIG. 14 is a diagram for explaining a conventional image reading apparatus using a reduced image forming system. The document 204 is placed on a platen glass 205 or sent on a flow reading glass 208 using an automatic document feeder 203. The information of the document illuminated by the fluorescent lamp 209 of the lamp unit 210 is turned back by the first mirror 201 and the second mirror 202 of the mirror unit 211 and is imaged on the reading element 213 by the reduction imaging lens 212. A reference white plate 206 adjusts a white level based on the reference white plate. The image processing unit 150 receives the output signal of the reading element 213 and generates a digital image from the signal.
[0003]
However, in recent years, it has been proposed to use a contact image sensor (hereinafter abbreviated as CIS) in an image reading device of a copying machine. FIG. 15 is a diagram for explaining an image reading apparatus using CIS. The document 204 is placed on a platen glass 205 or sent on a flow reading glass 208 using an automatic document feeder 203. The document information is read by the CIS 300. A reference white plate 206 adjusts a white level based on the reference white plate. The image processing unit 150 receives the output signal of the reading element 213 and generates a digital image from the signal.
[0004]
The reason why the reading apparatus using the CIS has become widespread is that the configuration is simpler than the reading system using the reduction optical system and the cost can be reduced. In addition, since the sensitivity is about 5 to 10 times higher, sufficient image quality can be obtained even with a relatively dark light source, so that the cost and power consumption of the illumination system can be reduced. For example, in the case of reading at about 30 sheets / min, the illuminance of the document surface of about 40,000 lux is required in the case of the reduction optical system, but about 4000 lux in the CIS using the Selfoc lens array (hereinafter abbreviated as SLA). It is enough.
[0005]
However, in a relatively bright lamp of 40,000 lux to 80,000 lux used in the reduction optical system, the relative emission amount of near-infrared rays as viewed from the emission spectrum was relatively small, but about 4000 lux used in CIS. When a relatively dark lamp was used, a phenomenon was observed in which the relative light emission of near-infrared rays increased.
[0006]
FIG. 16 is a view for explaining the emission spectrum of a 4000 lux relatively low-luminance Xe lamp. FIG. 17 is a view for explaining the emission spectrum of a high-intensity Xe lamp of 40000 lux. Comparing the two, the emission spectra in the visible light region of 400 to 700 nm are almost the same. However, in the near-infrared region of 800 to 1000 nm, the emission amount of near-infrared light with respect to the green peak near 550 nm is about three times larger for the 4000 lux lamp.
[0007]
FIG. 18 is a diagram illustrating the spectral sensitivity characteristics of RGB in a typical CCD image sensor. It can be seen that RGB has sensitivity to near infrared rays of 800 to 1000 nm. These are inherently unnecessary sensitivities. However, in spite of efforts to eliminate the sensitivity of near-infrared rays in the RGB primary color filters of dyes and pigments, they have not been realized yet, and such characteristics are not realized. Has become. Therefore, the CCD image sensor reads the near-infrared spectrum of the lamp, and as a result, RGB colors are mixed and the color discrimination is deteriorated. In addition, when a special color ink or the like using a color material having a high infrared spectral reflectance is read, there is a problem that the reading is unnecessarily bright. In addition, since this problem is worsened in proportion to the relative size of the near-infrared ray, the relatively low illuminance lamp of about 4000 lux described in FIG. 16 tends to be worse.
[0008]
In order to solve these problems, there has been proposed a device using a glass provided with an optical multi-coating such as an infrared cut glass before the CCD (see Patent Document 1). However, if an attempt is made to cover the A4 size 297 mm area with infrared cut glass, it becomes extremely expensive, on the order of several thousand yen to less than 10,000 yen, and is practically used for an inexpensive image reading apparatus. I can't.
[0009]
Therefore, in recent years, a near-infrared absorbing film for countermeasures against malfunction of a remote controller generated by infrared rays generated by a plasma display, or a near-infrared absorbing film developed to efficiently absorb near-infrared rays of a near-infrared light emitting laser diode in a DVD-R. Dyes and the like have been proposed. These have a structure in which a near-infrared absorbing dye is dispersed in a polymer resin.
[0010]
FIG. 19 is a diagram illustrating the spectral transmittance of the infrared absorbing film. In the figure, there is absorption in the near infrared region of 800 to 1000 nm, high light transmittance in the visible light region of 400 to 700 nm, and ideal characteristics that do not have large absorption at a specific wavelength in the visible light region. ing. That is, it is known that the emission spectrum in the visible light region hardly changes, and the near infrared peak at 800 to 1000 nm to be reduced can be reduced to about 1/10 to 1/20.
[0011]
[Patent Document 1]
JP-A-11-32177
[Problems to be solved by the invention]
However, these films are extremely thin, such as several tens of microns, have no rigidity, and are difficult to mount on a small CIS. Even with a relatively dark lamp of about 4000 lux, the surface of the tube is close to 100 ° C. during continuous lighting, so if a low heat-resistant film is placed near the lamp, the film may be degraded by heat. And other problems.
Furthermore, if an infrared absorbing film, such as a film made of a coating, whose surface is easily scratched is arranged in a so-called imaging system between the original and the CCD, the scratches on the film surface will affect the scanned image. It could have appeared as a streak.
[0013]
In view of such circumstances, an object of the present invention is to provide an image sensor capable of obtaining a high-quality image without cost and an image reading apparatus including the image sensor.
[0014]
[Means for Solving the Problems]
An image sensor according to the present invention includes a light source for irradiating a document, a light receiving unit for receiving reflected light from the document, and an imaging element for guiding the reflected light from the document to a light receiving unit. An image sensor that is held in a fixed manner, wherein a color cut film that cuts light of a specific wavelength included in the light source is held between the imaging element and the housing.
[0015]
The image sensor according to the present invention further includes a light source for irradiating the original, a light receiving unit receiving the reflected light from the original, and an imaging element for guiding the reflected light from the original to the light receiving unit. An image sensor that is integrally held, a part of a color cut film that cuts light of a specific wavelength included in the light source is inserted into a cutout portion of the housing, and the color cut film is inserted into the cutout. It is characterized in that it is held between an imaging element and the light receiving section.
[0016]
The image sensor according to the present invention further includes a light source for irradiating the original, a light receiving unit receiving the reflected light from the original, and an imaging element for guiding the reflected light from the original to the light receiving unit. An image sensor integrally held in a color cut film for cutting light of a specific wavelength included in the light source is formed in a substantially cylindrical shape, and the light source is disposed in the cylindrical shape of the color cut film. It is characterized by having done.
[0017]
The image sensor according to the present invention further includes a light source for irradiating the original, a light receiving unit receiving the reflected light from the original, and an imaging element for guiding the reflected light from the original to the light receiving unit. An image sensor integrally held in a color cut film that cuts light of a specific wavelength included in the light source is formed in a substantially box shape, and the light source is disposed in the box shape of the color cut film. It is characterized by having done.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.
(1st Embodiment)
FIG. 1 is a front cross-sectional view showing the first embodiment. In the figure, reference numeral 1 denotes a reading device main body, on which an automatic document feeder (ADF) 2 is mounted. Reference numeral 3 denotes a frame. On the upper surface of the frame 3, a reading glass 4 for reading a document conveyed from the ADF 2 and a book reading glass 5 used when reading the document in a stationary state are placed. ing. Further, a jump table 6 for scooping the original conveyed by the ADF 2 from the glass for reading flow 4 is also disposed on the upper surface of the frame 3 and between the glass for reading flow 4 and the glass for reading book 5. .
[0019]
Reference numeral 7 denotes a contact image sensor, which moves in the direction of the arrow in the drawing to convert the image of the original conveyed on the reading glass 4 or the original placed on the book reading glass 5 into image data. Take in as. The carriage 8 is supported by a guide shaft 9 provided in the vicinity of the center in the longitudinal direction, and can be freely moved along the guide shaft 9 below the flow-reading glass 4 and the book-reading glass 5 by a driving source (not shown). It has a configuration.
[0020]
Next, the configuration of the ADF 2 will be described.
The ADF 2 includes a pickup roller 11 for feeding the documents stacked on the document tray 10 one by one, a separation / conveyance roller 12 for preventing double feeding of the taken out documents, a separation pad 13, and a sheet for conveyance to a reading unit. Roller pairs 14 and 15, a pair of transport guides 16, a white roller 17 for flowing the original in the reading unit and pressing against the reading glass 4, a pair of discharge rollers 19 and 20 for sending the sheet to the discharge tray 18, It comprises a paper guide pair 21. The discharge tray 18 also has a function of a pressure plate for pressing a document upon reading a book against the book reading glass 5.
[0021]
Next, the operation of the apparatus will be described.
When the start key is pressed in a state where the original is placed on the original tray 10 of the ADF 2, first, the contact type image sensor 7 moves downward along the axial direction of the guide shaft 9 toward the lower side of the flow reading glass 4. It stops almost immediately below the white roller 17. In parallel with this operation, the original is fed by the pickup roller 11. The fed document is reliably separated one by one by the separation conveyance roller 12 and the separation pad 13, passes through the conveyance guide pair 16 by the conveyance force of the conveyance roller pair 14, is sent to the conveyance roller pair 15, and flows. It is sent between the white roller 17 which is the reading position of the reading and the flow-reading glass 4.
[0022]
At this time, since the contact type image sensor 7 has already reached the moving reading position, the image information of the document passing through the moving reading glass 4 can be sequentially read. As the reading progresses, the document passes over the white roller 17, is scooped by the jump table 6, and starts to be separated from the flow-reading glass 4. Thereafter, the document is conveyed by the pair of discharge rollers 19, passes through the pair of discharge guides 21, is discharged onto the discharge tray 18 by the pair of discharge rollers 20, and the reading operation of the first sheet is completed.
[0023]
If a plurality of documents are placed on the document tray 10, this operation is continuously repeated, and the reading operation ends when the reading of the last document is completed.
[0024]
Next, when the start key is pressed in a state where the document is not placed on the document tray 10, the apparatus main body 1 determines that the document is placed on the book reading glass 5. Then, the contact type image sensor 7 moves along the axial direction of the guide shaft 9 and reads an image placed on the book reading glass 5.
[0025]
FIG. 2 is a cross-sectional view of the CIS, and FIG. 3 is a perspective view of the CIS as viewed obliquely from above. In the figure, fluorescent lamps 22 and 23 illuminate a document. Reference numeral 24 denotes a SELFOC lens array (SLA), which is an equal-magnification image forming element, and forms information of a document on a reading element 25. Reference numeral 26 denotes a substrate on which the reading element 25 is mounted, all of which are integrated into a housing 27.
[0026]
Reference numeral 28 denotes an infrared cut film, which is incorporated into the hole 29 of the housing 27 so as to be sandwiched between the housing 27 and the SLA 24 as shown in FIG. With this infrared cut film 282, the amount of unnecessary 800 to 1000 nm infrared rays emitted from the fluorescent lamps 22 and 23 can be reduced to about 1/10 to 1/20. In addition, as the infrared cut film, any one that absorbs or reflects infrared components may be used as long as it can cut infrared rays. The same applies to all embodiments described below.
[0027]
Since the infrared cut film 28 is incorporated into the hole 29 of the housing 27 so as to be sandwiched between the housing 27 and the SLA 24, there is no problem such as movement during use of the apparatus and entry of foreign matter. Further, since no adhesive is used, there is no concern about image defects due to non-uniformity of adhesion and a change in transmittance due to deterioration of the adhesive. Further, since the wall of the housing 27 is arranged with the light sources 22 and 23 separated from each other, it is hardly affected by the heat generated from the light sources. Further, since the size may be the same as that of the SELFOC lens array 24, the size may be about several millimeters wide, and therefore, a method of cutting infrared rays at the lowest cost is realized.
[0028]
(Second embodiment)
Next, a second embodiment will be described with reference to FIGS.
FIG. 4 is a cross-sectional view of the CIS, and FIG. 5 is a perspective view of the CIS as viewed obliquely from below. The same components as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0029]
In the second embodiment, in particular, the infrared absorbing film 30 is held between the SLA 24 and the reading element 25 without adhering to the SLA 24. In this case, the infrared cut film 30 includes claws 30a, 30a ', 30b, 30b',. . . These are through holes 31a, 32a, 31b, 32b,. . . , The infrared cut film 30 is held by the housing 27.
[0030]
Also in this embodiment, the claws 30a, 30a ', 30b, 30b',. . . Are through holes 31a, 32a, 31b, 32b,. . . Since the device is inserted into the device, there is no problem such as movement during use of the device and entry of foreign matter. Further, since no adhesive is used, there is no concern about image defects due to non-uniformity of adhesion and a change in transmittance due to deterioration of the adhesive. Further, similarly to the first embodiment, since the fluorescent lamps 22 and 23 are arranged with the wall of the housing 27 separated from the fluorescent lamps 22 and 23, the fluorescent lamps 22 and 23 are hardly affected by the heat generated from the light source.
[0031]
Furthermore, since the infrared cut film 30 is not sandwiched by the SLA 24 as in the first embodiment, even when rework is required due to a scratch or the like during film production, it can be easily removed, and the yield can be improved. it can.
[0032]
(Third embodiment)
Next, a third embodiment will be described with reference to FIGS.
FIG. 6 is a cross-sectional view of the CIS, and FIG. 7 is a perspective view of the area around the fluorescent lamp of the CIS when viewed obliquely from above. The same components as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0033]
In the third embodiment, in particular, the infrared cut film 33 is formed in a cylindrical shape by superposing the ends of one film on each other and heat-welding them at the heat-welding portion 34. The fluorescent lamps 22 and 23 are individually passed through the cylindrical infrared cut film 33 and are incorporated in the housing 27 in this state.
[0034]
In the third embodiment, the amount of unnecessary 800 to 1000 nm infrared rays emitted from the fluorescent lamps 22 and 23 can be reduced to about 1/10 to 1/20 by the infrared cut film 33. In this case, since the infrared cut film 33 is arranged not in the image forming system but in the illumination system, there is no problem of the influence on the read image due to dust or scratches. Further, since no adhesive is used, there is no concern about image defects due to non-uniformity of adhesion and a change in transmittance due to deterioration of the adhesive.
[0035]
(Fourth embodiment)
Next, a fourth embodiment will be described with reference to FIGS.
FIG. 8 is a cross-sectional view of the CIS, and FIG. 9 is a perspective view of the area around the fluorescent lamp of the CIS when viewed obliquely from above. The same components as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0036]
In particular, in the fourth embodiment, the infrared cut film 35 is formed in a cylindrical shape by passing one end of one film through the other end. In this case, a plurality of claw portions 36a, 36b,. . . These are provided with through holes 37a, 37b,. . . , The infrared cut film 35 is formed in a cylindrical shape.
[0037]
In the fourth embodiment, the same effects as in the third embodiment can be obtained, but since it is not heat-welded as in the third embodiment, it can be removed even after completion. Therefore, for example, if the film has a crack or the like, the infrared cut film 35 can be easily removed, so that not only the yield at the time of manufacturing is improved, but also the exchangeability in the market is excellent.
[0038]
(Fifth embodiment)
Next, a fifth embodiment will be described with reference to FIGS.
FIG. 10 is a sectional view of the CIS, and FIG. 11 is a perspective view when the CIS is viewed from obliquely above. The same components as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0039]
Particularly in the fifth embodiment, the infrared cut film 38 is formed in a substantially U-shape by bending both ends of one film. In this case, the bent portion of each infrared cut film 38 has a plurality of holes 39, and the claw portions 40 provided on the housing 27 are inserted into these holes, so that the infrared cut film 38 has a substantially U-shape. It is kept as it is.
[0040]
In the fifth embodiment, the same effects as in the third and fourth embodiments can be obtained, but since it is not heat-welded as in the third embodiment, it can be removed even after completion. Therefore, for example, if the film has a crack or the like, the infrared absorbing film 35 can be easily removed, so that not only the yield at the time of manufacturing is improved, but also the exchangeability in the market is excellent.
[0041]
(Sixth embodiment)
Next, a sixth embodiment will be described with reference to FIGS.
FIG. 12 is a sectional view of the CIS. The same components as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0042]
In the sixth embodiment, similarly to the fifth embodiment, the infrared cut film 41 is formed in a substantially U-shape by bending both ends of one film. The difference from the fifth embodiment is that the fluorescent lamps 22 and 23 are not individually covered but are constituted by a single infrared cut film 41. As in the fifth embodiment, as in the fifth embodiment, the bent portion of the infrared cut film 41 has a plurality of holes 39 into which the claws 40 provided on the housing 27 are inserted.
[0043]
In this case, when the center portion of the infrared cut film 41 is bent in the direction of the SLA 24 because the infrared cut film 41 is thin, the center end portion 43 of the infrared cut film 41 is brought into contact with a portion 42 other than the lens surface of the SLA 24 so that the infrared cut film 41 is cut. The film 41 is held in a substantially U-shape.
[0044]
In the sixth embodiment, the same effects as those of the third to fifth embodiments can be obtained. However, since they are not heat-welded as in the third embodiment, they can be removed even after completion. If a crack or the like is present, the infrared cut film 41 can be easily removed, so that not only the yield at the time of manufacturing is improved, but also the exchangeability in the market is excellent.
[0045]
【The invention's effect】
As described above, according to the present invention, it is possible to realize an image sensor that reads high-quality images at low cost.
[Brief description of the drawings]
FIG. 1 is a sectional view of an image reading apparatus according to the present invention.
FIG. 2 is a sectional view of a CIS according to the first embodiment of the present invention.
FIG. 3 is a top perspective view of the CIS according to the first embodiment of the present invention.
FIG. 4 is a sectional view of a CIS according to a second embodiment of the present invention.
FIG. 5 is a lower perspective view of a CIS according to a second embodiment of the present invention.
FIG. 6 is a sectional view of a CIS according to a third embodiment of the present invention.
FIG. 7 is a perspective view around a fluorescent lamp of a CIS according to a third embodiment of the present invention.
FIG. 8 is a sectional view of a CIS according to a fourth embodiment of the present invention.
FIG. 9 is a perspective view around a fluorescent lamp of a CIS according to a fourth embodiment of the present invention.
FIG. 10 is a sectional view of a CIS according to a fifth embodiment of the present invention.
FIG. 11 is a top perspective view of a CIS according to a fifth embodiment of the present invention.
FIG. 12 is a sectional view of a CIS according to a sixth embodiment of the present invention.
FIG. 13 is a top perspective view of a CIS according to a sixth embodiment of the present invention.
FIG. 14 is a diagram illustrating a reduced image forming type image reading apparatus.
FIG. 15 is a diagram illustrating an image reading apparatus of the same magnification imaging type.
FIG. 16 is a diagram illustrating an example of an emission spectrum of a low-brightness xenon lamp.
FIG. 17 is a diagram illustrating an example of an emission spectrum of a high-brightness xenon lamp.
FIG. 18 is a diagram illustrating an example of spectral sensitivity characteristics of a reading element.
FIG. 19 is a diagram showing an example of the spectral transmittance of an infrared absorbing film.
[Explanation of symbols]
1 reading device body, 2 automatic document feeder (ADF), 3 frames, 4 flow reading glass, 5 book reading glass, 6 jump stand, 7 contact type image sensor, 8 carriage, 9 guide shaft, 10 document tray, DESCRIPTION OF SYMBOLS 11 Pickup roller, 12 Separation conveyance roller, 13 Separation pad, 14, 15 conveyance roller pair, 16 conveyance guide pair, 17 white roller, 18 discharge tray, 19, 20 discharge roller pair, 22, 23 fluorescent lamp, 24 SELFOC Lens array (SLA), 25 reading element, 26 substrate, 27 housing, 28 infrared cut film, 29 holes.

Claims (11)

An image in which a light source for irradiating a document, a light receiving unit receiving reflected light from the document, and an imaging element for guiding the reflected light from the document to the light receiving unit are integrally held in a housing. A sensor,
An image sensor, wherein a color cut film for cutting light of a specific wavelength included in the light source is held between the imaging element and the housing. An image in which a light source for irradiating a document, a light receiving unit receiving reflected light from the document, and an imaging element for guiding the reflected light from the document to the light receiving unit are integrally held in a housing. A sensor,
A part of a color cut film that cuts light of a specific wavelength included in the light source is inserted into a cutout portion of the housing, and the color cut film is held between the imaging element and the light receiving unit. Characteristic image sensor. An image in which a light source for irradiating a document, a light receiving unit receiving reflected light from the document, and an imaging element for guiding the reflected light from the document to the light receiving unit are integrally held in a housing. A sensor,
An image sensor, wherein a color cut film for cutting light of a specific wavelength included in the light source is formed in a substantially cylindrical shape, and the light source is disposed in the cylindrical shape of the color cut film. 4. The image sensor according to claim 3, wherein the color cut film is formed in a tubular shape by overlapping and heat-welding end portions of a single-leaf film material. 5. The image sensor according to claim 3, wherein the color cut film is formed in a cylindrical shape by passing one end of a single-leaf film material through the other end. An image in which a light source for irradiating a document, a light receiving unit receiving reflected light from the document, and an imaging element for guiding the reflected light from the document to the light receiving unit are integrally held in a housing. A sensor,
An image sensor, wherein a color cut film for cutting light of a specific wavelength included in the light source is formed in a substantially box shape, and the light source is disposed in the box shape of the color cut film. The image sensor according to claim 6, wherein the color cut film is formed in a substantially U-shape by bending both ends of a single-leaf film material. The image sensor according to any one of claims 1 to 7, wherein the color cut film is an infrared cut film. The image sensor according to any one of claims 1 to 8, wherein the imaging element is a selfoc lens for real-time coupling. The image sensor according to claim 1, wherein the light receiving unit is a photoelectric conversion element configured to photoelectrically convert light from the document. An image reading apparatus comprising the image sensor according to claim 1, wherein the image sensor is configured to read a document image while relatively moving and scanning the image sensor and the document.

Images